Microsoft co-founder and billionaire philanthropist Bill Gates has been hosting executives and entrepreneurs in London this week to boost investment in cutting-edge technologies promising big breakthroughs in tackling climate change.

Among those attending is Arvin Ganesan, who worked in the Obama administration and at Apple before joining the race to develop the next generation of long-storage batteries.

The power grids of the future will rely on better batteries to store excess renewable energy for when the sun isn't shining and the wind isn't blowing.

Ganesan is CEO of Fourth Power, a Boston-based company which says its prototype can store energy for weeks at a fraction of the cost of industry standard batteries.

AFP sat down with Ganesan to talk innovation, investment, and why he doesn't buy into "climate doomerism".

The following has been condensed and edited for clarity.

- What problem is your company trying to solve? -

"If we want low-cost renewables, you're going to need storage that is dead cheap, otherwise fossil fuels will remain the power source that is available whenever you want it. Unless we can tackle price and scalability, high amounts of renewables aren't going to work on a grid. And that's what Fourth Power does."

- Does it work? -

"I left Apple for this company. This isn't a hope and a dream. There's a lot of work that needs to happen, but this is really just an exercise in economics, and the equation is actually very simple.

"For the first time in my lifetime -- in a generation -- load growth is about to go up around the world because of data centers, AI, and electric vehicles. It's predicted to be huge.

"If the cost of renewables, plus storage, is less than the cost of building a new gas plant, then put aside philosophy, put aside climate change -- renewables and storage will always get deployed. So we have a very focused cost target that we need to hit in order to make that equation work."

- Your company has attracted funding from Gates, but so have other battery start-ups. Can you all survive? -

"The competition should not be among four or five for a small slice. It's between all these companies and whether they can be cheaper than new natural gas. So yes, all of them can succeed.

"All the companies here doing long-duration storage have a different way of approaching it. We are particularly focused on cost, scalability and flexible duration. Our batteries can go anywhere from 5 to 500 hours to whatever the customer needs.

"A rising tide raises all boats, so I don't think that there's any competition among these companies. It's fighting for a much bigger pie than just between the four of us."

- This isn't all about climate. Investors want to make money off the next big thing. -

"Absolutely. I think this is fitting into existing, market dynamics that allocates capital to technology that solves problems. And I think that is why there's optimism. These companies have customers, they have markets, and this doesn't feel like a lab experiment."

- Is there growing investor appetite for climate technology? -

"I think the market has been investing fairly deeply in climate tech solutions. It will be a success when there's not a category called climate tech, and when they're just thought of as good investments. You're starting to see that here. It's a super interesting and opportunistic moment. There are interesting people who have deep, serious backgrounds who are solving deeply existential and important problems."

- You sound optimistic about the future? -

"Climate doomerism is a problem. It demotivates people. But then you come here, you see all these companies, and many are going to pop in the next three or four years. These represent pretty major changes to the system. This is a really cool moment to see that.

"I think a lot of it has to do with storytelling. In the United States, people spend under ten minutes a year thinking about electricity, and not much beyond what they're paying and if the lights are on. But there's a massive change happening in the background.

"If that change is yielding a cleaner, more resilient, more reliable grid, that gives people hope that technology is actually solving their problems. I think that communicating that optimism is really good.

"I've worked in climate for a long time. I go through these waves where I ask what am I doing here? What is the future for my kids can look like?

"But even with the clunky politics we have, we're going to hit peak carbon in the next year or two. And you have all these trends in the marketplace that are just pushing towards cleaner technology, and that's a reason to celebrate."