A technology park in Kakaako is at least a 20-year-old state idea. But one with about as much space as you’d find in a 35-story tower could be realized by 2020 under a plan being advanced by an agency that controls land in the area.

The plan calls for creating a 5.5-acre campus in Kakaako Makai for startup companies, researchers, students and a state agency that has a lofty goal of creating 80,000 tech industry jobs with annual salaries of at least $80,000 in Hawaii by 2030.

State officials heading the project published a draft environmental assessment Wednesday that estimates an initial $39 million phase of what is being called the “Innovation Block” could be completed by 2018, followed by two more perhaps equally costly phases in 2020.

The project, on state land just Ewa of the University of Hawaii John A. Burns School of Medicine, is described as being critical to a state effort to foster a robust commercial high-tech industry that can help diversify the local economy from its heavy reliance on tourism, the military and, increasingly, luxury home development.

“The concept of the Innovation Block is to foster collaboration between public and private enterprises by intermingling and creating perceptible physical connections among high-tech development, commercial office, retail, and educational uses and their communities to promote the exchange of ideas and stimulate innovation,” the report said.

The state agency that owns the site, the Hawaii Community Development Authority, is leading the tech park effort with help from another state agency, the High Technology Development Corp., which is charged with facilitating growth of commercial high-tech enterprises in Hawaii.

HTDC would anchor the envisioned park in a 13,500-square-foot space dubbed the “Entrepreneur’s Sandbox.” This space would replace the agency’s existing headquarters at the Manoa Innovation Center, which UH plans to reclaim for its own use.

Other elements of the proposed park include a 150,000-square-foot building dubbed the “Innovation Hale” for commercial tech businesses, 140,000 square feet of space for higher education, 47,000 square feet of startup business incubation space, a 900-stall parking structure and a public plaza.

In all, about 350,000 square feet of tenant space would be in the complex of buildings rising up to six or seven stories.

If built, the Innovation Block would realize an old vision to have a tech park in Kakaako Makai. One chief promoter of this vision was Ben Cayetano, who as governor in the mid-1990s wanted to see a high-tech park, UH medical school, a Bishop Museum science and technology center, and a world-class aquarium built in Kakaako Makai.

The medical school was completed in 2005 on HCDA land, and was followed by a UH cancer research center in 2013.

The site now proposed for a tech park was previously going to be the site of the cancer center, which instead was built on an adjacent parcel of HCDA land.

HTDC, created in 1983, has been trying to develop three tech parks in the state and find new facilities to replace what it considers outdated space.

“The existing Manoa Innovation Center is 23 years old and was not designed to support the rapidly changing technological and infrastructural requirements of commercial high-technology development that have outpaced its original design,” the report said.

Robbie Melton, HTDC’s executive director and CEO, could not be reached for additional comments Wednesday.

HTDC said in its last annual report its efforts have produced positive results for the state. The agency reported that 64 companies used its two incubators last year, including 18 new companies and two that left the incubators after being acquired. The agency also said $8 was generated through revenue or funding for every dollar the state put into HTDC last year.

The agency added that its programs have helped companies produce $56 million in revenue, $24 million in investments and 296 high-wage jobs.

In December, HTDC announced its 80/80 plan to create 80,000 tech jobs paying $80,000 by 2030.

“While 80/80 is an ambitious goal, by collaborating with entrepreneurs, the business community and government, we can diversify our economy and build Hawaii’s reputation as a good place to do business,” Melton said in a statement at the time.

HTDC officially hooked up with HCDA early last year by handing over about $2.7 million to the development agency to spend on design and planning work for a tech complex that would include new facilities for HTDC.

That money was part of $3 million the Legislature appropriated for HTDC in 2012 to plan and design a new operating facility. HTDC spent $275,000 on the effort, which led to the Kakaako Makai site and an agreement to let HCDA take over the development effort.

HTDC also received $3 million last year from the U.S. Economic Development Administration for its anchor space that would also be financed and shared by DataHouse and Fisher Hawaii.

Still, getting legislative approval for much of what could be a more than $100 million tech park could prove challenging given competing state needs that include school improvements and a $160 million overhaul of the state’s psychiatric hospital.

The Innovation Block currently houses a storage yard and a parking lot with 414 stalls for UH’s medical school and cancer center.

HCDA proposes developing the tech project in three phases. An initial phase would include about half the tech space, including HTDC facilities and the commercial space. A second phase would include the business incubator and the parking garage, which would also provide parking for UH. The third phase would be the higher-education facility.