Note 10 — Property, Plant, and Equipment NRG’s major classes of property, plant, and equipment were as follows:
## Table 0 ##
Note 11 — Goodwill and Other Intangibles Goodwill — NRG’s goodwill arose primarily in connection with the acquisition of Texas Genco in 2006.
During 2010, the Company’s goodwill balance increased by $155 million due to the acquisition of Green Mountain Energy, as discussed in Note 3, Business Acquisitions, and decreased by $5 million due to the sale of Padoma, as discussed in Note 4, Discontinued Operations and Dispositions.
As of December 31, 2010, there was no impairment to goodwill.
As of December 31, 2010 and 2009, NRG had approximately $660 million and $721 million, respectively, of goodwill that is deductible for U. S.  income tax purposes in future periods.
Intangible Assets — The Company’s intangible assets as of December 31, 2010, primarily reflect intangible assets established with the acquisitions of various companies in 2010, 2009, and 2006, and are comprised of the following: ?
Emission Allowances — These intangibles primarily consist of SO2 and NOx emission allowances established with the 2006 Texas Genco acquisition and also include RGGI emission credits which NRG began purchasing in 2009.
These emission allowances are held-for-use and are amortized to cost of operations, with NOx allowances amortized on a straight-line basis and SO2 allowances and RGGI credits amortized based on units of production.  ?
Development rights — Arising primarily from the acquisition of a solar business in 2010, these intangibles are amortizable to depreciation and amortization expense on a straight-line basis over the estimated life of the related project portfolio.  ?
Energy supply contracts — established with the acquisitions of Reliant Energy and Green Mountain Energy, these represent the fair value at the acquisition date of in-market contracts for the purchase of energy to serve retail electric customers.
The contracts are amortized to cost of operations based on the expected delivery under the respective contracts.  ?
In-market fuel (gas and nuclear) contracts — These intangibles were established with the Texas Genco acquisition in 2006.
The power contracts are amortized to revenues based on contracted volumes over the life of each contract and the fuel contracts to cost of operations over expected volumes over the life of each contract.  ?
Customer contracts — established with the acquisitions of Reliant Energy, Green Mountain Energy, and Northwind Phoenix as discussed further in Note 3, Business Acquisitions, these intangibles represent the fair value at the acquisition date of contracts to provide electricity, primarily to Reliant Energy’s and Green Mountain Energy’s C&I customers.
These contracts are amortized to revenues based on expected volumes to be delivered for the portfolio.  ?
Customer relationships — These intangibles represent the fair value at the acquisition date of acquired businesses’ customer base, primarily for Reliant Energy and Green Mountain Energy.
The customer relationships are amortized to depreciation and amortization expense based on the expected discounted future net cash flows by year.
Commercial Operations Overview NRG seeks to maximize profitability and manage cash flow volatility through the marketing, trading and sale of energy, capacity and ancillary services into spot, intermediate and long-term markets and through the active management and trading of emissions allowances, fuel supplies and transportation-related services.
The Company's principal objectives are the realization of the full market value of its asset base, including the capture of its extrinsic value, the management and mitigation of commodity market risk and the reduction of cash flow volatility over time.
NRG enters into power sales and hedging arrangements via a wide range of products and contracts, including PPAs, fuel supply contracts, capacity auctions, natural gas derivative instruments and other financial instruments.
In addition, because changes in power prices in the markets where NRG operates are generally correlated to changes in natural gas prices, NRG uses hedging strategies that may include power and natural gas forward sales contracts to manage the commodity price risk primarily associated with the Company's coal and nuclear generation assets.
The objective of these hedging strategies is to stabilize the cash flow generated by NRG's portfolio of assets.
NRG also trades electric power, natural gas, oil, weather and related commodity and financial products, including forwards, futures, options and swaps, primarily through its ownership of Boston Energy Trading and Marketing, or BETM, which was acquired in the acquisition of EME.
BETM seeks to generate profits from volatility in the price of electricity, capacity, fuels and transmission congestion by buying and selling contracts in wholesale markets under guidelines approved by the Company's risk management committee.
Coal and Nuclear Operations The following table summarizes NRG's U. S.  coal and nuclear capacity and the corresponding revenues and average natural gas prices and positions resulting from coal and nuclear hedge agreements extending beyond December 31, 2014, and through 2018 for the Company's Gulf Coast region:
## Table 1 ##
(a) Net coal and nuclear capacity represents nominal summer net MWcapacity of power generated as adjusted for the Company's ownership position excluding capacity from inactive/mothballed units, see Item 2 - Properties for units scheduled to be deactivated.
(b) Forecasted generation dispatch output (MWh) based on forward price curves as of December 31, 2014, which is then divided by number of hours in a given year to arrive at MW capacity.
The dispatch takes into account planned and unplanned outage assumptions.
(c) Includes amounts under power sales contracts and natural gas hedges.
The forward natural gas quantities are reflected in equivalent MWh based on forward market implied heat rate as of December 31, 2014, and then combined with power sales to arrive at equivalent MWh hedged which is then divided by number of hours in a given year to arrive at MW hedged.
The coal and nuclear sales include swaps and delta of options sold which is subject to change.
For detailed information on the Company's hedging methodology through use of derivative instruments, see discussion in Item 15 - Note 5, Accounting for Derivative Instruments and Hedging Activities, to the Consolidated Financial Statements.
Includes inter-segment sales from the Company's wholesale power generation business to the retail business.
(d) Percentage hedged is based on total coal and nuclear sales as described in (c) above divided by the forecasted coal and nuclear capacity.
(e) Represents U. S.  coal and nuclear sales, including energy revenue and demand charges.
The following table provides the details of NRG's operating revenues:
## Table 2 ##
(a) Inter-segment sales and net derivative gains and losses included in operating revenues.
Energy revenue consists of revenues received from third parties as well as from the Company's retail businesses, for sales of electricity in the day-ahead and real-time markets, as well as bilateral sales.
It also includes energy sold through long-term PPAs for renewable facilities.
In addition, energy revenue includes revenues from the settlement of financial instruments and net realized trading revenues.
Capacity revenue consists of revenues received from a third party at either the market or negotiated contract rates for making installed generation capacity available in order to satisfy system integrity and reliability requirements.
Capacity revenue also includes revenues from the settlement of financial instruments.
In addition, capacity revenue includes revenues received under tolling arrangements, which entitle third parties to dispatch NRG's facilities and assume title to the electrical generation produced from that facility.
Retail revenue, representing operating revenues of NRG's retail businesses, consists of revenues from retail sales to residential, small business, commercial, industrial and governmental/institutional customers, revenues from the sale of excess supply into various markets, primarily in Texas, as well as product sales.
Mark-to-market for economic hedging activities includes asset-backed hedges that have not been designated as cash flow hedges and ineffectiveness on cash flow hedges.
Contract amortization revenue consists of the amortization of the intangible assets for net in-market C&I contracts established in connection with the acquisitions of Reliant Energy and Green Mountain Energy, as well as acquired power contracts, gas derivative instruments, and certain power sales agreements assumed at Fresh Start and Texas Genco purchase accounting dates related to the sale of electric capacity and energy in future periods.
These amounts are amortized into revenue over the term of the underlying contracts based on actual generation or contracted volumes.
Other revenues include revenues generated by the Thermal Business consisting of revenues received from the sale of steam, hot and chilled water generally produced at a central district energy plant and sold to commercial, governmental and residential buildings for space heating, domestic hot water heating and air conditioning.
It also includes the sale of high-pressure steam produced and delivered to industrial customers that is used as part of an industrial process.
Other revenues also consists of operations and maintenance fees, or O&M fees, construction management services, or CMA fees, sale of natural gas and emission allowances, and revenues from ancillary services.
O&M fees consist of revenues received from providing certain unconsolidated affiliates with services under long-term operating agreements.
CMA fees are earned where NRG provides certain management and oversight of construction projects pursuant to negotiated agreements such as for the GenConn, Cedar Bayou 4 and certain solar construction projects.
Ancillary services are comprised of the sale of energy-related products associated with the generation of electrical energy such as spinning reserves, reactive power and other similar products.
Other revenues also include unrealized trading activities.
Item 7 — Management's Discussion and Analysis of Financial Condition and Results of Operations The discussion and analysis below has been organized as follows: ?
Executive Summary, including the business environment in which NRG operates, a discussion of regulation, weather, competition and other factors that affect the business, and significant events that are important to understanding the results of operations and financial condition; ?
Results of operations, including an explanation of significant differences between the periods in the specific line items of NRG's Consolidated Statements of Operations; ?
Financial condition addressing credit ratings, liquidity position, sources and uses of cash, capital resources and requirements, commitments, and off-balance sheet arrangements; and ?
Critical accounting policies which are most important to both the portrayal of the Company's financial condition and results of operations, and which require management's most difficult, subjective or complex judgment.
As you read this discussion and analysis, refer to NRG's Consolidated Statements of Operations to this Form 10-K, which presents the results of the Company's operations for the years ended December 31, 2017, 2016, and 2015, and also refer to Item 1 to this Form 10-K for more detailed discussion about the Company's business.
Executive Summary NRG Energy, Inc. , or NRG or the Company, is a leading integrated power company built on the strength of a diverse competitive electric generation portfolio and leading retail electricity platform.
NRG aims to create a sustainable energy future by producing, selling and delivering electricity and related products and services in major competitive power markets in the U. S.  in a manner that delivers value to all of NRG's stakeholders.
The Company owns and operates approximately 30,000 MW of generation; trades wholesale energy, capacity and related products; transacts in and trades fuel and transportation services; and directly sells energy, services, and innovative, sustainable products and services to retail customers under the names “NRG”, "Reliant" and other retail brand names owned by NRG.
Business Environment The industry dynamics and external influences affecting the Company and its businesses, and the power generation and retail energy industry in general in 2017 and for the future medium term include: Capacity Markets — Capacity markets are a major source of revenue for the Company.
Centralized capacity markets exist in ISO-NE, MISO, NYISO and PJM.
Bilateral markets exist in CAISO and MISO.
These auctions are either an annual market held three years ahead of the delivery period as in the case of PJM and ISO-NE, or six months to one month ahead as in the case of NYISO.
Many variables affect the prices derived in these auctions.
These variables include the load forecast, the target reserve margin, rules surrounding demand response, capacity performance penalties, capacity imports and exports from the region, new generation entrants, slope of the demand curve, generation retirements, the cost of retrofitting old generation to meet new environmental rules, expected profitability of the units themselves in the energy market and various other auction rules.
In theory, a high capacity price indicates that the ISO doesn't have sufficient generation capacity against its needed reserve margin and new construction should enter the market.
Similarly, a low capacity price suggests the market is over-built and units should retire.
The Company has seen many swings in the pricing for capacity markets and the rules in many of the markets are undergoing significant changes, as discussed in this Management's Discussion and Analysis of Financial Condition and Results of Operations.
Commodities Markets — The price of natural gas plays an important role in setting the price of electricity in many of the regions where NRG operates power plants.
Natural gas prices are driven by variables including demand from the industrial, residential, and electric sectors, productivity across natural gas supply basins, costs of natural gas production, changes in pipeline infrastructure, and the financial and hedging profile of natural gas consumers and producers.
In 2017, average natural gas prices at Henry Hub were 26.3% higher than in 2016.
If long-term gas prices decrease, the Company is likely to encounter lower realized energy prices, leading to lower energy revenues as higher priced hedge contracts mature and are replaced by contracts with lower gas and power prices.
NRG's retail gross margins have historically improved as natural gas prices decline and are likely to partially offset the impact of declining gas prices on conventional wholesale power generation.
To further mitigate this impact, NRG may increase its percentage of coal and nuclear capacity sold forward using a variety of hedging instruments, as described under the heading "Energy-Related Commodities" in Item 15 — Note 5, Accounting for Derivative Instruments and Hedging Activities, to the Consolidated Financial Statements.
consume significant amounts of energy, and we may in the future incur additional or increased capital, operating and other expenditures from changes due to new or increased climate-related and other environmental regulations.
We could also incur substantial liabilities, including fines or sanctions, enforcement actions, natural resource damages claims, cleanup and closure costs, and third-party claims for property damage and personal injury under environmental and common laws.
The Foreign Corrupt Practices Act of 1977 and local anti-bribery laws, including those in Brazil, China, Mexico, India and the United Kingdom (where we maintain operations directly or through a joint venture), prohibit companies and their intermediaries from making improper payments to government officials for the purpose of influencing official decisions.
Our internal control policies and procedures, or those of our vendors, may not adequately protect us from reckless or criminal acts committed or alleged to have been committed by our employees, agents or vendors.
Any such violations could lead to civil or criminal monetary and non-monetary penalties and/or could damage our reputation.
We are subject to a number of labor and employment laws and regulations that could significantly increase our operating costs and reduce our operational flexibility.
Additionally, changing privacy laws in the United States (including the California Consumer Privacy Act, which will become effective in January 2020), Europe (where the General Data Protection Regulation became effective in 2018) and elsewhere have created new individual privacy rights, imposed increased obligations on companies handling personal data and increased potential exposure to fines and penalties.
Item 1B.
UNRESOLVED STAFF COMMENTS There are no unresolved SEC staff comments.
Item 2.
PROPERTIES We operate locations in North America, including the majority of U. S.  states, South America, Europe, Asia and Australia.
We lease our principal offices in Atlanta, GA.  We believe that our existing production capacity is adequate to serve existing demand for our products and consider our plants and equipment to be in good condition.
Our corporate and operating facilities as of September 30, 2019 are summarized below:

<table><tr><td> </td><td colspan="2">As of December 31,</td><td rowspan="2"> Depreciable   Lives</td></tr><tr><td> </td><td>2010</td><td>2009</td></tr><tr><td> </td><td colspan="2">(In millions)</td><td> </td></tr><tr><td>Facilities and equipment</td><td>$13,820</td><td>$13,023</td><td>1-40 Years</td></tr><tr><td>Land and improvements</td><td>580</td><td>621</td><td></td></tr><tr><td>Nuclear fuel</td><td>314</td><td>286</td><td>5 Years</td></tr><tr><td>Office furnishings and equipment</td><td>199</td><td>153</td><td>2-10 Years</td></tr><tr><td>Construction in progress</td><td>1,400</td><td>533</td><td></td></tr><tr><td>Total property, plant and equipment</td><td>16,313</td><td>14,616</td><td></td></tr><tr><td>Accumulated depreciation</td><td>-3,796</td><td>-3,052</td><td></td></tr><tr><td>Net property, plant and equipment</td><td>$12,517</td><td>$11,564</td><td></td></tr></table>
<table><tr><td>Gulf Coast</td><td>2015</td><td>2016</td><td>2017</td><td>2018</td><td>AnnualAverage for2015-2018</td></tr><tr><td></td><td colspan="5">(Dollars in millions unless otherwise stated)</td></tr><tr><td>Net Coal and Nuclear Capacity (MW)<sup>(a)</sup></td><td>6,290</td><td>6,290</td><td>6,290</td><td>6,290</td><td>6,290</td></tr><tr><td>Forecasted Coal and Nuclear Capacity (MW)<sup>(b)</sup></td><td>4,739</td><td>5,097</td><td>5,261</td><td>5,225</td><td>5,081</td></tr><tr><td>Total Coal and Nuclear Sales (MW)<sup>(c)</sup></td><td>5,629</td><td>2,909</td><td>1,251</td><td>1,000</td><td>2,697</td></tr><tr><td>Percentage Coal and Nuclear Capacity Sold Forward<sup>(d)</sup></td><td>119%</td><td>57%</td><td>24%</td><td>19%</td><td>55%</td></tr><tr><td>Total Forward Hedged Revenues<sup>(e)</sup></td><td>$2,224</td><td>$1,128</td><td>$502</td><td>$435</td><td></td></tr><tr><td>Weighted Average Hedged Price ($ per MWh)<sup>(e)</sup></td><td>$45.11</td><td>$44.15</td><td>$45.82</td><td>$49.67</td><td></td></tr><tr><td>Average Equivalent Natural Gas Price ($ per MMBtu)<sup>(e)</sup></td><td>$3.99</td><td>$4.28</td><td>$4.42</td><td>$4.75</td><td></td></tr><tr><td>Gas Price Sensitivity Up $0.50/MMBtu on Coal and Nuclear Units</td><td>$-12</td><td>$118</td><td>$188</td><td>$197</td><td></td></tr><tr><td>Gas Price Sensitivity Down $0.50/MMBtu on Coal and Nuclear Units</td><td>$40</td><td>$-109</td><td>$-183</td><td>$-187</td><td></td></tr><tr><td>Heat Rate Sensitivity Up 1 MMBtu/MWh on Coal and Nuclear Units</td><td>$12</td><td>$104</td><td>$144</td><td>$155</td><td></td></tr><tr><td>Heat Rate Sensitivity Down 1 MMBtu/MWh on Coal and Nuclear Units</td><td>$8</td><td>$-86</td><td>$-128</td><td>$-138</td><td></td></tr></table>
<table><tr><td></td><td colspan="5">Year Ended December 31,</td></tr><tr><td></td><td>2017</td><td>2016</td><td>2015</td><td>2014</td><td>2013</td></tr><tr><td></td><td colspan="5">(In millions)</td></tr><tr><td>Energy revenue<sup></sup></td><td>$3,549</td><td>$4,122</td><td>$4,923</td><td>$4,960</td><td>$3,638</td></tr><tr><td>Capacity revenue<sup></sup></td><td>1,197</td><td>1,236</td><td>1,368</td><td>1,201</td><td>936</td></tr><tr><td>Retail revenue<sup></sup></td><td>6,385</td><td>6,336</td><td>6,910</td><td>7,372</td><td>6,315</td></tr><tr><td>Mark-to-market for economic hedging activities</td><td>21</td><td>-572</td><td>-143</td><td>690</td><td>-185</td></tr><tr><td>Contract amortization</td><td>-56</td><td>-56</td><td>-40</td><td>-12</td><td>-32</td></tr><tr><td>Other revenues</td><td>490</td><td>543</td><td>425</td><td>536</td><td>287</td></tr><tr><td>Corporate/Eliminations</td><td>-957</td><td>-1,097</td><td>-1,115</td><td>-1,937</td><td>-2,139</td></tr><tr><td>Total operating revenues<sup>(a)</sup></td><td>$10,629</td><td>$10,512</td><td>$12,328</td><td>$12,810</td><td>$8,820</td></tr></table>

Question: What was the total amount of elements greater than 4000 in 2015? (in million)
Answer: 16658