The top five ways companies are integrating renewables into the grid are:
1. Intelligent Demand Response
2. Microinverters and Maximum Power Point Trackers
3. Wind Energy Management Tools
4. The Virtual Power Plant
5. The Hybrid Solar-Gas Power Plant
Explanations of each of these with videos are below.
Intermittent renewables at high penetrations will bring new challenges for the grid. But how big will they be? And is it true that wind and solar will necessarily need storage or natural gas back-up at high levels?
The International Energy Agency wanted to know, so it modeled a variety of high-penetration scenarios in eight geographic regions around the world. Hugo Chandler, a senior policy analyst with the IEA explains the organization’s findings to Climate Progress:
Variability is not just some new phenomenon in grid management. What we found is that renewable energy is not fundamentally different. The criticisms of renewables often neglect the complementarities between different technologies and the way they can balance each other out if spread over certain regions and energy types.
Grid operators are constantly working to balance available supply with demand – it’s what they do. There are always natural variations that cause spikes in demand, reductions in supply or create disturbances in frequency and voltage. Once you see there are a variety of ways to properly manage that variability, you start whittling away at the argument that you always need storage or a megawatt of natural gas backup for every megawatt of renewable energy.
Theoretical modeling is important. But what companies are doing in reality?
Here’s five of the top methods for integrating renewable energy into the grid – proving that intermittency isn’t the show-stopper that critics make it out to be.
Intelligent Demand Response
Intelligent demand response is often called the “killer app” of the smart grid. Demand response is not a new concept – but the “intelligent” part is still somewhat new.
The demand-response leader, EnerNOC, is now applying this concept to renewable energy. The company announced earlier this year that it would work with a Northwestern transmission operator to help manage demand to meet the fluctuating output of wind electricity in the system. EnerNOC president David Brewster calls it “the perfect dancing partner for wind.” By ramping up demand at facilities during time of peak supply and lowering demand when supply drops off, the grid can respond to changing conditions in real time without the need for storage.
Microinverters and Maximum Power Point Trackers
Inverters are the gateway to the grid – turning Direct Current electricity from solar PV systems to grid-friendly Alternating Current. Over the past several years, there’s been a revolution in inverter technologies that allow project owners to more effectively regulate system performance. One technology, the microinverter, is installed on the back of individual panels, turning each module into its own unit and providing real-time data on how each is operating. Therefore, if clouds roll over a PV system, the “Christmas tree light effect” is avoided, and each panel still functions normally, maximizing the output of a system – sometimes by 20% or more.
Speaking of maximizing output, that’s where Maximum Power Point Trackers (MPPT) come in. These pieces of power electronics are also installed on the back of individual panels. But they’re not microinverters; instead, they boost voltage to an optimal range for a central inverter, thus allowing the device to run more efficiently. By allowing a system owner to control a PV plant at the module level, you can boost performance on the module level and regulate voltage even as weather patterns change.
Wind Energy Management Tools
SCADA systems that remotely monitor wind farm performance have been around for years – but there are a host of new applications being developed that allow grid operators and utilities monitor system-wide performance in an easier, more compelling way.
The Wind Energy Management System from the Portuguese company Logica is a great example. The company manages over 3 gigawatts of wind farms in the U.S. and Europe using its WEMS, which allows for real-time monitoring of a set of geographically dispersed wind plants – providing the tools to balance voltage, ramp wind farms up and down quickly, and plan for maintenance.
A company like EnerNOC provides the tools for better management on the demand side; a company like Logica provides the tools for better integration on the supply side.
The Virtual Power Plant
Virtual power plants combine intelligent demand response with supply-side management software, bringing distributed renewable energy plants together to form a “virtual” centralized resource.
We previously wrote about Germany’s Regenerative Combined Power Plant, a project that proved existing renewable energy technologies could provide 100% of the country’s electricity. The project blended three wind farms worth 12.6 MW, 20 solar PV plants totaling 5.5 MW, four biogas systems equaling 4 MW and a pumped storage system with 8.4 GWh of storage. By using geographically dispersed renewable resources that compliment one another, the plant operators were able to meet needs on the grid as supply and demand shifted. The project shows that with better information technologies and a balanced set of resources, the intermittency issue can be dealt with.
The Hybrid Power Plant
While innovative grid management tools will allow us to scale wind and solar without an equivalent MW to MW backup, there will definitely be a need to better integrate renewables and fossil energies to boost output and maximize current infrastructure.
Concentrating Solar Power can be a great way to increase efficiencies of newer fossil fuel-based infrastructure that may be around for a while. A number of companies are integrating direct-steam CSP technologies into coal or natural gas plants. FPL recently finished a 75 MW combined CSP/natural gas plant in Florida, with plans to add 500 more MW of hybrid plants in the coming years; Areva Solar is building a 44-MW plant at a coal facility and a 250-MW hybrid solar/natural gas plant in Australia; and GE, which recently invested in e-Solar, plans to integrate CSP technology into its natural gas plants, boosting power plant efficiencies substantially.
In an ideal world, CSP would be developed on its own to phase out fossil-based plants. And that is happening. But in order to scale these technologies, drop costs and better utilize power plants that are in operation (or switch from burning coal to far more efficient natural gas), the hybrid approach is a very attractive option. Here’s how one type of direct-steam CSP plant works:
To categorically claim that intermittent renewables can’t scale without hurting the grid ignores the very real innovations that are evolving today.
As the IEA’s Hugo Chandler explains: “We want to explode the myth that there’s a technological limit.”
Below are the earlier comments from the Facebook commenting system:
Some really smart technology is being developed to actually manage energy usage rather than letting so much go to waste.
Thanks for the interesting article. The quote from the International Energy Agency hits the nail on the head about how wind energy is integrated onto the power grid:
1. There has always been a large amount of variability and uncertainty on the power system (chiefly from electric demand changing and from conventional power plants experiencing unexpected “forced outages,” taking 1000+ MW offline instantaneously,
2. Adding even a large amount of wind or solar energy to the grid typically only adds a small incremental amount to overall power system variability, as most of the variability introduced by wind or solar is cancelled out by opposite changes in other sources of variability, and.
3. Grid operators have a number of tools to deal with variability and uncertainty on the power system today, and those tools can be readily used to deal with the incremental variability and uncertainty that comes from adding large amounts of wind or solar to the grid.
While it is exciting that new technologies like demand response are being developed to provide grid operators with even more tools to manage all types of variability on the power system, it is important to emphasize that large amounts of wind and solar are being efficiently and reliably integrated onto the grid today. More than 15% of the electricity comes from wind in Ireland, Spain, Portugal, and Denmark; in the U.S., 8% of electricity on the main Texas grid and more than 15% of the electricity produced in Iowa last year came from wind energy.
It is also important to emphasize that grid operators only need to balance the aggregate supply and demand for electricity on the grid. A common misconception is that the variability of each individual resource on the grid needs to be managed, and discussion of pairing dedicated storage or a dedicated “backup” power plant with a particular resource, or combining several resources to create a virtual power plant or a microgrid, often falls into that trap. Over 100 years ago we built a power grid that combines all sources of variability on the grid so that I can turn my air conditioner on and off without having a dedicated battery or other backup system attached to my house, just as a large coal or nuclear plant can be built without building dedicated backup to step in when that plant experiences an unexpected outage; trying to dis-aggregate the grid would be a step backwards.
Overall, the article did a good job of explaining how the power grid works and how wind energy is integrated onto the grid.
American Wind Energy Association.
Yes, the idea of integrating solar thermal with existing coal or natural gas power plants is a very good one, I think. Even better would be to transform the coal fired power plants to biomass with carbon capture and storage, with solar augmentation. This would create carbon negative to carbon neutral power plants, even if some fossil fuels are added to the mix. This would add flexibility, and allow power plants in the southern regions of the country to add increased solar energy to the mix. Conversely, power plants along navigable eastern rivers with more plentiful supplies of biomass or charcoal from upstream on the river could add increased biomass with CCS. Flexibility is good, as is retrofitting existing facilities to be more carbon neutral or even carbon negative.
must admit I was disappointed when the german virtual power plant vid zoomed out to show only germany as the scale of the experiment. it seems like the obvious end product of fuel-switching there will be a supply management grid extending from one end of the mediterranean to the other, and latitudinally from the arctic to near the equator.
Adding solar or wind to existing power plants is a neat way to add renewable capacity using existing transmission connections, minimizing the costs and delays of integrating renewables.
The Green Awakening Economy is on a roll. Happily as the GAE gains traction the GOBP will be left in the dust. Good riddance to bad rubbish…
Thanks for showing how companies are deploying these technologies.
Awesome! The 100 per cent renewable powered economy is in sight.
I think its only up for all. Step by step.
These are interesting new developments that I had previously read about.
However, I have to say that the basic premise of the article which appears to be that wind and solar do not require 100% backup is simply wrong. I have to wonder why anyone would try to suggest that this simple fact is not correct: There are times when the sun doesn’t shine and the wind doesn’t blow. To be more specific, fixed flat panel solar output varies from 0% at dawn to 100% and noon and back to 0% at sunset even if there isn’t a cloud in the sky. And, as we all know solar produces no output at night.
Specifically, I noticed that one example included storage and possible backup while another example included 100% backup.
As the article alluded to, the issue is “grid penetration”. We need to understand that the grid already has peaking power generation units which are basically the same as backup. This means that we can add intermittent renewables to the grid using the existing peaking capacity for backup. I have seen estimates of 20% to 30% which seems reasonable although there is already wind energy produced at night with no market for it (more grid might fix that). There is also an additional market in some areas for summer solar for peaking.
However, when we exceed the limit, we will run into a problem when we find out that the variability of wind and solar is not really a stationary stochastic process and the results of the simulations, therefore, do not hold up in reality — there will be times when the output of a significant number of wind and solar units will simultaneously drop to zero. If you doubt this, consult the theoretical analysis of Benoît Mandelbrot on why Gaussian distributions do not produce the correct result — 5-sigma events happen more often in the real world than would be expected from standard probability theory.
June 16 at 2:28am
Ok I went to go and talk with this guy who was inventing a different way to make a car from a stop to get faster speed because most eletrical cars need all litiumn batterys but with his you can use the cheaper battery for cruz and litiumn for take off.
June 16 at 10:52am
Anyway he also had some very cool ways to help the grid. Battery storage.(old Batterys) durning like peak times they can take the old batterys energy to put it into the grid when they need it like when its dark. What that means is there are other ways to save durning no wind and sun times and the grid can use this so they don’t even have to use any other kind of energy(Coal or Nuclear) Our homes can be with little cost be a transforer for the grid durn off hours.
June 16 at 10:55am
We have step up peaks for this also. Like a condenser storage. I heard about the new battery storage in cell phones that will last years beyound. The tec is here don’t let people say it dos’nt work because look all around you the smart people are doing it.
June 16 at 10:57am