There's never a summer vacation in the world of cleantech investment. 

In recent weeks, we’ve tracked nearly $70 million in investment in the space, ranging from free EV charging business models, to next-generation batteries, to experimental carbon capture technologies. And that's not all. Here’s a roundup of the deals uncovered by GTM Research analyst Paulina Tarrant and others on our team.

San Francisco-based startup Volta Charging has raised $21 million from investors, according to a filing with the U.S. Securities and Exchange Commission. The latest document amends a previous filing and brings the total round to $32 million. This funding comes on top of a reported $11.5 million round in 2016, a $4.5 million Series A round in 2015, and roughly $3.2 million in seed financing, as well as about $6 million in debt financing to support its first rollouts. 

Volta is building a business on the proposition of EV chargers, located at parking lots around the state, that are free to both EV drivers wanting to charge up, and the property owners or businesses it has partnered with. Volta says it can accomplish this by leveraging advertising revenues and the value of drawing EV drivers to its partners’ locations.

According to its website, Volta now has hundreds of Level 2 chargers open for business, mostly in California, but also in Hawaii, Arizona, Washington state, and Illinois, including a deal to supply free EV charging to Chicago’s United Center arena. 

Vionx, a maker of vanadium redox flow batteries, has raised $26 million, according to this SEC filing. The Woburn, Mass.-based startup has previously raised at least $79 million in venture capital financing, including $58 million last year, with investors including VantagePoint Capital Partners, Starwood Energy Group, and the New York State Energy Research and Development Authority. 

Vionx, formerly known as Premium Power, has two systems operating today in Massachusetts: a 160-kilowatt, 4-hour system at an Army Reserve base at Fort Devens, and a 500-kilowatt, 6-hour system at Holy Name High School in Worcester. Vionx has built partnerships with other companies to help move the product, including Siemens, Jabil, 3M and UTC, where the technology was developed. 

Last year, Vionx teamed up with New Energy Risk to create a performance insurance policy that covers energy, power, round-trip efficiency and availability of its flow batteries. Flow batteries offer multi-hour-duration energy storage that lithium-ion can’t match, at least in a pound-for-pound comparison. But it will be difficult for flow batteries, as well as other insurgent energy storage technologies, to challenge lithium-ion's dominance in terms of market share, constant cost reductions, and economies of scale. 

Inventys, a Vancouver, Canada-based company with a technology to capture carbon dioxide emissions from power plants, has raised $11 million in financing. The round was led by OGCI Climate Investments, the billion-dollar investment fund created by the Oil and Gas Climate Initiative, along with previous investors The Roda Group and Chevron Technology Ventures. 

The new investment comes on top of a $10 million round last year, and will help fund its 30 tonne-per-day carbon dioxide capture pilot plant demonstration program with Husky Energy, as well as a factory in Burnaby, British Columbia used to build its “structured adsorbent beds.”

Inventys says its VeloxoTherm process, a “direct intensified rapid cycle temperature swing adsorption (i-TSA) process that is largely material-agnostic,” can absorb carbon dioxide as it’s being emitted from power plants. For those who understand such things, here’s an explanation from the company’s website: “By leveraging the tailored heat and mass transfer properties of structured adsorbent laminate, this advanced technology unlocks the new advanced solid adsorbent materials. A shorter cyclic process of about 60 seconds, versus 60 minutes, means higher overall throughput and smaller footprint."

Carbon capture and sequestration (CCS) will be a vital technology to combat climate change in a world that will still rely on burning fossil fuels for energy for the foreseeable future. In the United States, Congress passed a 45Q tax credit for CCS projects in February, and in June passed the USE It Act, which supports research for the technology, through the Senate Environment and Public Works committee. Even so, recent reports, including one from Wood Mackenzie and another from the Energy Futures Initiative, show that analysts remain divided on the prospects for CCS.

Recent weeks have also seen several large-scale financing deals for clean technology deployments. Vivint Solar announced it has closed $811 million in debt financing through capital market issuance of $466 million from Vivint Solar Financing managed by Credit Suisse Securities and Citigroup Global Markets, as well as a $345 million private placement by Vivint Solar Financing IV arranged by Credit Suisse. 

Vivint Solar plans to use the debt to “repay in full and cut down on the balance of certain debt facilities of Vivint Solar and its subsidiaries for general corporate purposes.” The company also plans to provide "back-leverage financing" for a portfolio of 16 tax equity funds and a subsidiary that owns a PV portfolio of 575 megawatts and more than 86,000 residential PV systems. Vivint has struggled, alongside Tesla’s SolarCity, through the shifts in the solar market from third-party ownership to solar loans for homeowners and businesses. 

In other solar news, Sunlight Financial, a technology-enabled finance company for residential solar and energy storage lending, raised a $50 million investment from growth equity investor FTV Capital last month. The proceeds will be used to expand Sunlight's product suite, enhance its technology platform, add strategic partners, and deepen existing partnerships.

FTV Capital managing partner Brad Bernstein and vice president Mike Vostrizansky have joined the company’s board of directors as part of the transaction. Sunlight Financial claims it has secured more than $1 billion of capital for loans to homeowners to date.

Finally, in Ireland, “Light-as-a-Service” provider UrbanVolt closed a $65 million financing deal with U.K. investment company Low Carbon. UrbanVolt upgrades commercial buildings to LED lighting for no upfront capital cost, giving them roughly 75 percent savings on lighting energy costs, as well as the commensurate carbon emissions reductions.

UrbanVolt earns a portion of these savings as a service charge and maintains the systems for five years. Earlier this year, UrbanVolt launched a solar-as-a-service model offering that enables commercial and industrial customers to access solar PV on a subscription basis.