Issues and challenges

Location

A key challenge to any major infrastructure project, including renewable energy facilities, is location.  Most people say they favor renewable energy, but when it comes to building a project, they may say “Not in My Back Yard.”

Renewable resources are not shared equally among islands.  Oahu has the most people and thus the greatest electricity demand but limited sites and resources for renewable energy projects.  Hawaii Island has abundant geothermal energy, a resource no other island presently uses for electricity. 

Each Hawaiian Island has a separate stand-alone grid and it presently is not possible to move electricity between islands.  Some renewables are not always available, like sunshine, wind, even the water in small streams.  Having a large percentage of variable or “as available” energy on small, remote grids such as those in Hawaii is challenging, making it harder to maintain reliability and power quality.  In addition to variable renewable energy sources, the electric utilities need “firm” energy sources which are available on-demand 24 hours a day to meet its customers' energy needs.

Supporting facilities, including power lines, substations, transformers and other equipment also pose a challenge.  Most renewable energy projects are built in remote areas, far from population centers.  Infrastructure to bring the power from these places to the grid – and to store or “smooth” variable “as available” energy -- is expensive and adds to the cost of the electric power.

Still, Hawaiian Electric, Maui Electric and Hawaii Electric Light Company are working hard to increase renewable energy.  This includes encouraging other companies to develop renewable projects, adding power lines and substations needed for renewable projects and working on ways to smooth and store “as available” power.
  

24-hour Availability

Our demand for electricity continues 24 hours of every day.  A typical week day, as shown in the chart below, starts with low demand around midnight.  Demand starts climbing in the early morning hours as we get up for work and school, levels off at a “mini-peak” around noon and then reaches a true peak between 5 p.m. and 9 p.m. before falling off again toward midnight.  For much of the year in Hawaii the evening peak is the time of highest demand.  This is when people come home from work and school and hotels, restaurants and shops are lighting up and busy.

NOTE: Solar insolation is the amount of power available from sunlight per square meter of area.
  

Firm vs. Intermittent

Because electricity is constantly being used 24 hours a day, we need reliable sources of energy.  Traditional generators are considered “firm” because they provide continuous power.  Some renewable sources – waste-to-energy systems like H-Power on Oahu and geothermal plants like Puna Geothermal Ventures on Hawaii Island - are also considered firm sources of power.

However, many renewable energy sources are considered “intermittent” or “as-available” because they do not provide continuous power.  For example, the output of a wind farm will depend on minute-to-minute, second-to-second changes in wind speed and direction.  Also, wind continues to blow overnight, when the demand for electricity is lowest.  Rainy days or passing clouds can reduce the output of a photovoltaic system.  Output from hydroelectric systems depends on the amount of rainfall and the flow of streams.

These kinds of intermittent or as-available renewable systems usually require “firm” generators to serve as back-ups or some type of battery system to store the electricity they generate.  Currently, these kinds of battery systems are still being developed and are expensive investments.

A solar water heater is able to store water heated from the sun and provide hot water even during the night.   However, storing photovoltaic power requires batteries that are currently expensive.  Batteries large enough to store wind power for long-enough periods at a reasonable cost are just now being developed and tested.

As energy storage devices, including new generations of batteries, become available it will make it easier to reliably add more renewable energy to the grid.
  

Cost
 

Oil is becoming more expensive and harder to find.  Also, we now understand that using fossil fuel contributes to global climate change.  Hawaii’s oil-based energy system that has worked well for about a century must change.

Switching from an oil-based energy system to a renewables/efficiency based system will take investment in new facilities and infrastructure and, in the case of “as available” energy sources like wind, sufficient and firm backup to keep the lights on.  While this will increase electricity costs, the more renewable energy that can be added using fixed price formulas, the less we will need to use oil, which is increasingly more expensive, to produce electricity.  That can result in more stable and lower prices to customers compared where prices were headed.

(Currently, in Hawaii, more than 50% of a typical electric bill goes to pay for fuel, mainly oil).

Some people believe that renewable energy must be cheaper because “fuel” such as sunlight, wind, volcanic heat, ocean waves and flowing water are “free.”  However, this ignores the cost of converting these sources to electricity, and making them reliable.

Here are some things to remember about cost:

Environmental & cultural concerns

Although they have many environmental benefits, renewable energy resources do have environmental and cultural impacts.  Hawaiian Electric respects cultural concerns and works hard to lessen adverse environmental impacts of its projects.

Every energy project raises environmental and cultural issues that can delay or stop the project if they are not addressed in advance, with openness and respect.

   •   Geothermal

When development of geothermal energy was first proposed on Hawaii Island, some who opposed the project cited cultural concerns stemming from Hawaiian beliefs in Pele, the volcano goddess believed to be responsible for the formation of the Hawaiian Islands.  Others expressed worries about the health effects of hydrogen sulfide emissions from geothermal projects and that development and operations, such as well drilling, could be noisy and disruptive.

Some people also expressed concerns about the slight possibility that injection wells might contaminate drinking water sources.

All of these concerns must be addressed through thorough environmental reviews and extensive consultation with the native Hawaiian community.

   •   Wind

One concern raised for some wind project includes the large expanses of land needed by big wind farms.  For some projects, the land around the wind turbines can be used for general grazing or growing crops.

Some people also think the wind turbines are an eyesore, noisy, a contributor to erosion, and are concerned about potential harm to birds flying in the area.  Thorough environmental reviews and habitat conservation plans are important to addressing these concerns.

   •   Biomass & biofuel

Agricultural projects to grow biomass and biofuel feed stocks typically require large expanses of land and large amounts of water for irrigation and processing.  Burning the biomass fuel source produces air emissions.  Pesticides and fertilizers required to grow the fuel source crops may also raise concerns.  The key is to grow biomass or biofuel feedstocks in a sustainable manner.  Fortunately, new technologies including pollution controls and combustion engineering have advanced so that emissions from biomass in industrial facilities are generally less than in the case of fossil fuels. ⁽¹⁾

A waste-to-energy plant, like H-POWER on Oahu, does not require land for crops.  Waste-to-energy may actually protect land by reducing the requirement for noxious land fills.

(1) Institute for Energy Research (http://www.instituteforenergyresearch.org/energy-overview/biomass/)

   •   Hydro

Building hydroelectric facilities can impact aquatic habitats by changing water flow in rivers and streams.
  

Reliability
 

In a technological, computer-based world, we depend on reliable, high-quality electricity more than ever.  Maintaining such power while increasing renewable electricity on our grids is a challenge we must understand and solve.

“Reliable” means electricity is available when needed, 24 hours a day, 365 days a year.

“Power quality” refers to electricity delivered at a smooth 60 hertz (cycles per second).  The grid is designed to operate at this frequency.  If frequency changes beyond a certain level, the grid is designed to protect itself from expensive, long-term damage.  This can be done by turning off some customers if necessary and, in extreme cases, shutting down entirely.

In our homes and businesses, electronic devices are also designed to operate on the 60 hertz frequency.  In sensitive electronic devices electrical surges and ebbs can disrupt or distort operations and even damage or destroy the devices.

Many renewable resources are variable, or intermittent.  Wind is a good example. Hawaii’s typical tradewinds may blow harder on some days, softer on others, and at times not at all.  Wind direction and speed can change minute to minute. All this affects the electrical output of wind turbines.

On small, stand-alone grids like those in the Hawaiian Islands, these fluctuations must be offset by “firm” generators.  One challenge is that the wind can change quicker than typical electric generators.  Maintaining 60 hertz frequency can strain generators (and the people who operate them).

This problem is less severe for large utilities on the continental U.S. because the variable renewable resource may be a much smaller percentage of total generation than on Hawaii’s small grids.  As a result, power can be picked up from interconnected utilities.

New technologies -- like the electronic shock absorber invented and patented by engineers at Hawaiian Electric Company -- can help smooth the ebbs and surges of wind in the short term.

Large-scale electric storage -- including very large chemical, mechanical and electronic “batteries” -- is being developed.  But some technologies are in very early stages of development.  At present, large batteries or other storage can be very expensive, adding to the cost of every kilowatt hour of electricity produced.
  

Energy Storage

A great technical and commercial challenge for renewable energy is energy storage.  As-available energy sources such as solar and wind can’t be counted on to provide power 24 hours a day.  Energy storage, in the early stages of development, can help make renewable electricity available when it is needed.  Stored energy can be used in three ways. One is load leveling, holding energy produced when demand is low and using it when demand is high.  Compressed air energy storage and pumped storage hydro work well for this.

Another is ramping.  Energy from renewable sources like wind typically rises and drops off faster than typical firm-energy generators can ramp down or up to meet the change.  Stored electricity can be used to fill in the difference.  Compressed air energy storage, pumped storage hydro and flow-type batteries work well for ramping.  Renewable electricity output can fluctuate minute to minute, causing problems in voltage regulation.  Batteries, super capacitators, flywheels and Superconducting Magnetic Energy Storage can help.

Electricity storage systems on a large or utility scale are at different stages of technical and commercial development and still quite costly.

Pumped storage hydro is a proven form of energy storage for electric utilities.  There are over 150 plants with 22,000 MW of capacity in United States and 78,000 MW of PSH installed worldwide.  Pumped storage hydroelectricity is a method of storing and producing electricity to supply high peak demands by pumping water to a reservoir at a higher elevation during off-peak periods and producing electricity using flowing water during on-peak periods.  Several natural geological features are needed, including adequate close land areas divided by adequate elevation.  There must also be an adequate water supply, though in some cases the lower reservoir is the ocean and sea water is used.

Studies have explored the possibilities of pumped storage hydro at Koko Crater and Ka'au Crater; on Hawaii Island at Puu Waawaa and Puu Anahulu in North Kona, Puu Enuhe in Kau and at Kaupulehu/Kukio.  On Maui, sites have been considered at Maalaea, Honokowai in the Kaanapali area, Kohama near Lahaina and upcountry at Ulupalakua.

PSH challenges include siting, permitting, water availability, cost and the long lead time for development.

Hawaiian Electric continues to explore, monitor and study energy storage solutions in conjunction with the U.S. Department of Energy and General Electric, a leader in the renewable energy field.
  

Curtailment
 

Even when renewable energy is available, utilities sometimes must cut back on “as-available” variable sources during off-peak periods of low electricity use.

Generation and consumption of electricity must be in balance at all times to maintain reliability and power quality.  As customer demand for power drops, for example overnight, generation must be turned down or off.  If electricity generated exceeds demand, the electric system can become unstable.  A minimum level of firm generation sources must be kept on line to ensure reliability for customers 24/7.  This can mean that not all of the energy from variable sources like wind can be used during period of low electricity demand.

Increasing the use of overnight charging for electric vehicles is one way to increase demand during off-peak times to utilize more as-available renewable energy and reduce fossil fuel for transportation.
  

Land
 

Land in Hawaii is limited and some renewable energy sources require a lot of it.  Also, most renewable energy projects must be located where the renewable energy source (wind, geothermal, solar, etc.) is.  It may be in a remote area away from existing power lines where new substations and transmission lines must be built to get power to the grid.  That leads to higher costs.

With increasing residential and commercial development on our islands, especially Oahu, it is hard to find less populated space for energy projects like wind farms that have a high profile and visibility.