Press release

REL ANNOUNCES CLOSING OF BUSINESS COMBINATION BETWEEN SOLID POWER, INC. AND DECARBONIZATION PLUS ACQUISITION CORPORATION III

16 December 2021

·      Solid Power announced closing of its business combination with DCRC on 8 December 2021

·      Solid Power became the only pure-play solid-state battery company to trade on the public markets

·      Solid Power common stock and warrants began trading on Nasdaq Global Select Market on 9 December 2021 under the symbols "SLDP" and "SLDPW," respectively

·      Gross proceeds to Solid Power from the transaction of $542.9 million from fully committed $195 million PIPE and $347.9 million of cash held in trust net of redemptions; only 0.6% of shares held by public stockholders of DCRC were redeemed

·      Of the shares voted at the special meeting of DCRC's stockholders, over 99.9% voted to approve the business combination

Riverstone Energy Limited ("REL") announces the closing of the previously announced business combination between Solid Power, Inc. ("Solid Power"), an industry leading developer of all solid state battery cells for electric vehicles, and Decarbonization Plus Acquisition Corporation III ("DCRC"), a special purpose acquisition corporation sponsored by an affiliate of REL. Solid Power announced the closing on 8 December 2021 and the combined company's common stock and warrants began trading on the Nasdaq Global Select Market under the ticker symbols "SLDP" and "SLDPW," respectively, on 9 December 2021.

Solid Power received gross proceeds from the transaction of approximately $542.9 million from its fully committed $195 million PIPE and the receipt of approximately $347.9 million of cash from DCRC's trust account net of redemptions. Of the shares voted at the special meeting of DCRC stockholders on 7 December 2021, over 99.9% voted to approve the business combination. In addition, only 0.6% of shares held by DCRC's public stockholders were redeemed.

On 23 March 2021, REL made a $0.5 million investment in DCRC's sponsor in connection with DCRC's initial public offering.

On 15 June 2021, REL committed an additional $20 million to the PIPE that was raised in connection with the business combination transaction.

Prior to the business combination, REL purchased 1.66 million shares of Solid Power, which converted to shares of the combined company in connection with the business combination.

This investment, along with the recent decarbonisation investments in Decarbonization Plus Acquisition Corporation II & IV, FreeWire Technologies, GoodLeap and Hyzon Motors, demonstrates REL's continued efforts to increase its exposure to the global energy transition thematic while also providing the opportunity to create value for its shareholders.

About Solid Power:

Solid Power is an industry-leading developer of all-solid-state rechargeable battery cells

for electric vehicles and mobile power markets. Solid Power replaces the flammable

liquid electrolyte in a conventional lithium-ion battery with a proprietary sulfide-based

solid electrolyte. As a result, Solid Power's all-solid-state battery cells are expected to

be safer and more stable across a broad temperature range, provide an increase in

energy density compared to the best available rechargeable battery cells, enable less

expensive, more energy-dense battery pack designs and be compatible with traditional

lithium-ion manufacturing processes.

For more information, visit https://solidpowerbattery.com/.

About Riverstone Energy Limited:

REL is a closed-ended investment company that invests exclusively in the global energy industry across all sectors. REL aims to capitalise on the opportunities presented by Riverstone's energy investment platform.  REL's ordinary shares are listed on the London Stock Exchange, trading under the symbol RSE. REL has 13 active investments spanning decarbonisation, oil and gas, renewable energy and power in the Continental U.S., Western Canada, Gulf of Mexico and Europe.

For further details, see www.RiverstoneREL.com.

Neither the contents of Riverstone Energy Limited's website nor the contents of any website accessible from hyperlinks on the websites (or any other website) is incorporated into, or forms part of, this announcement.

LEI: 213800HAZOW1AWRSZR47

About Riverstone Holdings LLC:

Riverstone is an energy and power‐focused private investment firm founded in 2000 by David M. Leuschen and Pierre F. Lapeyre, Jr. with approximately US$41 billion of capital raised. Riverstone conducts buyout and growth capital investments in the E&P, midstream, oilfield services, power, and renewable sectors of the energy industry. With offices in New York, London, Houston, Mexico City, Amsterdam and Menlo Park, Riverstone has committed nearly US$43 billion to more than 200 investments in North America, Latin America, Europe, Africa, Asia, and Australia.

For further details, see www.RiverstoneLLC.com