We’ve known how to produce clean, renewable energy for like, years. Definitely more than a century in the “modern” sense of producing electricity, and way longer than that if you include things like windmills, sailboats, and the way Romans used the tide to flush away their shit.

Yet despite some fairly significant advances on the tech side of things in the twentieth century, and despite the promise of cheap, clean energy just around the corner, most of our energy still comes from fossil fuels of one type or another.

Nuclear has been put forth as a “clean” energy source, in that its pollutants can theoretically be contained. But while NASA tells us that nuclear is less harmful than fossil fuels, I feel compelled to point out that solar plants, hydroelectric plants, geothermal wells, and wind farms can’t suddenly wipe out whole towns and render large areas uninhabitable for generations. You can keep your meltdown safeguards; I’ll take the option(s) where meltdowns aren’t even a thing.

So what’s going on in the world of earth, wind, water, and sun? There’s some cool stuff…and some meh stuff…but mostly, there’s an idea of when stuff might be trickling down to the likes of us.

Geothermal Energy

Often overlooked, geothermal power is really efficient and easy to use…once it’s been accessed. Getting to the heat trapped below the Earth’s surface has been the deal-breaker for commercial-sized projects in most areas (except for Iceland—you win this round, you volcanic island nation you!). Drilling deep enough for a sizable heat draw costs millions, but HyperSciences is working on a projectile-based rust-penetration method that might change things. Even fossil fuel giant Shell invested $1 million in their technology.

Whether or not that will truly unlock cheap geothermal all over the globe remains to be seen, but it won’t be in your backyard any time soon. Alta Rock Energy, backed by Silicon Valley luminaries like Google and Khosla Ventures, was making more immediate waves with its geothermal purchases and efficiency advances last year, but there hasn’t been any recent news. Perhaps the world of geothermal has stopped turning in light of renewables more familiar with the spotlight?

Solar Power

Right now, despite the Sun being the largest and most universally available renewable energy resource, only around 1% of energy in the US is solar-produced. There are governmental and economic forces at work that might help solar spread, but what we really need is new (or improved) tech that makes solar affordable for the masses.

Hawaii, with the highest cost of electricity in the nation, has been a solar leader, and Elon Musk‘s SolarCity is rolling out a solar-battery station on Kaua’i that should deliver solar-derived juice even in the evening hours—a first for a residential/consumer solar power plant. Meanwhile, newer and better types of solar cells are being developed, and AngelList counts a total of 475 startups in the solar space. Many of those startups, however, are software-focused or otherwise devoted to the logistics of solar rather than actually turning Sun beams into electricity. You know, the fun stuff.

Of 20 companies in solar-focused startup-helper Powerhouse‘s portfolio, only two—IRFTS and Avalon Battery—seem to be developing and manufacture solar-related hardware; everyone else is marketing, data-ing, or logistical…ing. With the “get to market” mentality most startups have, the intensive R&D needed to make a cheaper and more efficient solar cell is being conducted in the world’s universities, and is probably a good decade away from consumers.

Batteries like Tesla’s Powerwall (which SolarCity is likely to use a variation of) are a big step forward, but abundant on-the-spot creation is the real dream of a brighter tomorrow.

Wind Power

GE is doing cool stuff with Big Data to make wind farms more efficient, and also recently rolled out a new more productive turbine, but the startup space is as hushed as a summer breeze; AngelList counts only 64 startups involved in “wind,” and not all of those are in wind energy (there are also zero startups having to do with flatulence in this category, which I must say I found depressing).

Few of them are making headlines, but Accio Energy is working on a whole new way of generating electricity from wind without using turbines, and they just got $4.5 million from the US Department of Energy. They may be at the forefront of tomorrow’s wind technology…but the massive government funding means they’re nowhere near market, so I’m not holding my breath (#MiniPun) for their long-winded solution (#PrimoPun) to our energy demands.

Altaeros Energies has some cool inflatable turbines, but they’re designed for more rural and especially high-altitude, on-the-spot use, and probably won’t be doing anything for our national grid anytime soon.

It looks like we’re probably about a decade away from major consumer use of wind power. Maybe more though if it continue to take a back seat to solar.

Hydropower

Hydroelectric power stations have been around almost since electricity was first harnessed but the technology hasn’t changed a whole lot. Moving water spins a turbine, and the more efficiently you can get that turbine to create electricity the better. The process takes a major investment and long research periods; it’s not like we haven’t been trying to improve the electric motor since its inception, so turbine-based energy production isn’t likely to get “disrupted” in the next few years.

A few startups and newer companies are putting in a valiant effort, though, including Marine Current Turbines which boasts of having the first commercial-capacity tidal based hydroelectric turbine system in the world. Hydrovolts is also in the mix, making smaller-scale hydroelectric feasible again (it used to be relatively common in the early days before the grid).

As far as when there will be some hydroelectric near you, there either already is some, or there isn’t too likely to be any. A few companies like Gravity Renewables are taking a business approach to bringing more hydroelectric plants back online, but the hardware investment is still way too high compared to any cost savings to build new hydroelectric plants where alternative energy sources already exist.

Despite efforts from governments and a handful of startups, abundant clean and renewable energy is still just out of reach and it’s going to take a few more years for that to change. But chin up! There’s a good chance we quickly solve that pesky polar bear problem (no polar bears, no problem)!